LNA with controlled phase bypass

Abstract

In electronic circuits having various gain states, small gain phase shift differences required among various gain states may pose a challenging problem. The disclosed methods and devices provide solution to such challenge. Electronic circuits are described wherein a first path including an amplifier may be bypassed by a second path including only passive elements and for gain states smaller than 0 dB. In such electronic circuits, a phase shifter included in the second path can be adjusted to address the required phase shift among various gain states.

What is claimed is: 
     
       1. An electronic circuit comprising:
 a first path and a second path, each connecting a signal input of the electronic circuit with a signal output of the electronic circuit such that the first path and the second path connect to the same signal input; 
 wherein:
 the first path comprises an amplifier; 
 at least one of the first path or the second path comprises one or more adjustable variable phase shifters configured to achieve desired gain phase shift differences between various gain states of the electronic circuit; and 
 the second path is configurable to bypass the first path. 
 
 
     
     
       2. The electronic circuit of  claim 1 , wherein the set gain phase shift difference requirement is such that the phase shift difference lies within +/−30 degrees. 
     
     
       3. The electronic circuit of  claim 1 , wherein the set gain phase shift difference requirement is such that the phase shift difference lies within +/−10 degrees. 
     
     
       4. The electronic circuit of  claim 1 , wherein at least one of the first or the second path comprises one or more attenuators. 
     
     
       5. The electronic circuit of  claim 4 , further comprising one or more parallel switches each coupling across a corresponding attenuator of the one or more attenuators. 
     
     
       6. The electronic circuit of  claim 5 , wherein each of the first and the second path comprises series switches used to switch in or switch out the first or the second path. 
     
     
       7. The electronic circuit of  claim 6 , wherein the plurality of gain states comprise a first gain state and a second gain state and wherein:
 in the first gain state, an overall gain between the signal input and the signal output is larger than 0 dB; and 
 in the second gain state, the overall gain between the signal input and the signal output is smaller than 0 dB. 
 
     
     
       8. The electronic circuit of  claim 7 , wherein the overall gain between the signal input and the signal output is adjusted by switching the one or more attenuators in and out using the one or more parallel switches. 
     
     
       9. An electronic circuit with a plurality of gain states, comprising:
 a serial arrangement of an amplifier and one or more adjustable variable phase shifters; the serial arrangement connecting a signal input of the electronic circuit with a signal output of the electronic circuit such that the first path and the second path connect to the same signal input; and 
 one or more parallel switches coupled each across a corresponding adjustable variable phase shifter of the one or more variable phase shifters configured to achieve desired gain phase shift differences between various gain states of the electronic circuit. 
 
     
     
       10. The electronic circuit of  claim 9 , further comprising one or more attenuators, and wherein in each gain state, the overall gain between the signal input and the signal output is adjusted by switching the one or more attenuators in or out and using the one or more parallel switches. 
     
     
       11. The electronic circuit of  claim 9 , wherein the set gain phase shift difference requirement is such that the phase shift difference lies within +/−30 degrees. 
     
     
       12. The electronic circuit of  claim 9 , wherein the set gain phase shift difference requirement is such that the phase shift difference lies within +/−10 degrees. 
     
     
       13. A method of adjusting gain phase shift in an electronic circuit with a plurality of gain states comprising:
 connecting a signal input of the electronic circuit with a signal output of the electronic circuit by a first path comprising an amplifier; 
 connecting the signal input with the signal output by a second path; 
 including one or more adjustable variable phase shifters in the first path or the second path; 
 in a gain state of the plurality of gain states, configuring the second path to bypass the first path; and 
 adjusting through the one or more adjustable variable phase shifters gain phase shift differences among the plurality of gain states according to a set gain phase shift difference requirement. 
 
     
     
       14. The method of  claim 13 , wherein at least one of the first or the second path comprises one or more attenuators. 
     
     
       15. The method of  claim 14 , further comprising selectively switching in and out the one or more attenuators to adjust an overall gain between the signal input and the signal output. 
     
     
       16. The method of  claim 15 , wherein the set gain phase shift difference requirement is such that the phase shift difference lies within +/−10 degrees.